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Terahertz frequency selective surfaces using heterostructures based on two-dimensional diffraction grating of single-walled carbon nanotubes

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International Journal of Smart and Nano Materials 2023年第1期14卷 21-35页

作者： Pavel Evgenjevich Timoshenko Alexander Lerer Sergei Bernardovich Rochal Pavel E.Timoshenko faculty of physics Southern Federal UniversityRostov-on-DonRussia southern federal university Rostov-on-DonRussia

For single-walled carbon nanotubes(SWCNTs)with a length of 1-50μm,the surface plasmon-polariton(SPP)resonance is within the terahertz frequency range;therefore,SWCNT lattices can be used to design frequency-selective surface(FSS).A numerical model of electromagnetic wave diffraction on a two-dimensional periodic SWCNT lattice can be described by an integro-differential equation of the second-order with respect to the surface current along *** equation can be solved by the Bubnov-Galerkin *** dependence of reflecting and transmitting electromagnetic waves for FSSs near the SPP resonance is studied *** is shown that the resonances are within the lowerfrequency part of the terahertz *** also estimate the relaxa-tion frequency of an individual SWCNT and demonstrate the applic-ability of the Kubo formula for graphene conductivity to array of strips similar in size to SWCNTs under consideration.

关键词： Carbon nanotubes gratings graphene surface plasmon polaritons dielectric response functions

Possibilities of the practical use of a stationary strain gradient in the interelectrode volume of unpolarized ferroceramic plates

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Journal of Advanced Dielectrics 2020年第1期10卷 61-67页

作者： Yu.N.Zakharov V.P.Sakhnenko I.A.Parinov I.P.Raevsky M.A.Bunin V.A.Chebanenko M.A.Zaerko E.I.Sitalo A.A.Pavelko L.I.Kiseleva research institute of physics and physics faculty southern federal university rostov-on-don 344090 Russia institute of Mathematics Mechanics and Computer Sciences Southern Federal UniversityRostov-on-Don 344090Russia federal research Centre The southern Scientific Centre of the Russian Academy of The Sciences rostov-on-don 344004 Russia

It has been established that in plates made of hot-pressed ferroelectric ceramics PZT-19(Tc=300℃),after metal electrodes from Ag are burned into opposite surfaces with different depths of mechanical damage,counter-directional stationary deformation gradients and,accordingly,internal electric displacement fields create a stationary flexoelectric *** a result,unpolarized ceramics below the Curie temperature become a pyroelectric,and above it become a pyroelectric *** polishing the less damaged surface and replacing the Ag(valency v=3)electrode with Cr(v=6)by thermal evaporation in vacuum from the intact surface,a new thermally stable polarization is created,directed from the damaged surface in the interelectrode *** plates have an asymmetric dielectric hysteresis loop,retain the values of the pyroelectric effect and piezoelectric effect in the ferroelectric phase,as well as the bolometric effect in the paraelectric phase after repeated heating cycles to 400℃ and cooling to T_(norm).

关键词： Strain gradient unpolarized ferroceramic pyroelectric effect bolometer

The complex oxides with octahedral structures:Existence areas and phase transitions

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Journal of Advanced Dielectrics 2020年第1期10卷 80-92页

作者： G.A.Geguzina research institute of physics Southern Federal University 194 Stachki Ave.Rostov-on-Don344090 Rostov OblastRussia

The experimental and calculated data on the existence of complex oxides in solid state with the octahedral structures of four families,namely perovskites,Bi-containing layered perovskite-like ones,tetragonal tungsten bronzes and pyrochlores,and about their phase transitions are systematized and summarized on the basis of the quasi-elastic or geometric models of these *** has been established that similar existence areas and similar correlations between the interatomic bond strains in their structures,on the one hand,and the temperatures of their ferroelectric or antiferroelectric phase transitions,on the other hand,are observed for all of them,despite the differences in the compositions and structures of these oxides,but taking into account their similar parameters.

关键词： Complex oxides with octahedral structures perovskite structure Bi-containing layered perovskite-like structures tetragonal tungsten bronze structure pyrochlore structure

Crystal structure and dielectric properties of layered perovskite-like solid solutions Bi_(3-x)Gd_(x)TiNbO_(9)(x=0,0.1,0.2,0.3)with high Curie temperature

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Journal of Advanced Dielectrics 2020年第1期10卷 9-15页

作者： S.V.Zubkov research institute of physics Southern Federal University Stachki Ave.194Rostov-on Don344090Russia

The Aurivillius phases(APs)[Bi_(2)O_(2)]2t[A_(m-1)B_(m)O_(3m+1)]2-are well-known ferroelectrics with high Curie *** piezoceramics Bi_(3-x)Gd_(x)TiNbO_(9)(BiGdTiNb,x=0,0.1,0.2,0.3)were prepared by a solid-state reaction *** structural and electrophysical characteristics of BiGdTiNb ceramics have been *** to the data of powder X-ray diffraction,all the compounds are single-phase with the structures of two-layer APs(m=2)with the orthorhombic crystal lattice(space group A21am).The temperature dependence of the relative permittivityε/ε_(0)(T)of the compounds was measured and showed that the Curie temperature of perovskite-like oxides Bi_(3-x)Gd_(x)TiNbO_(9) increases linearly with an increase in the substitution parameter x to T_(C)=950℃.The activation energies of charge carriers have been found in different temperature ranges.

关键词： Aurivillius phases Bi_(3-x)Gd_(x)TiNbO_(9) Curie temperature T_(C) tolerance factor

Structural features of the A_(2)TiSi_(2)O_(8)(A-Ba and Pb)compounds

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Journal of Advanced Dielectrics 2020年第5期10卷 43-47页

作者： Svetlana Weber Alla Lebedinskaya Daniil Rudsky Yuri Kabirov Anzhela Rudskaya Michael Kupriyanov The Department of physics Southern Federal University 5 Zorge Str.Rostov-on-Don 344090Russia research institute of physics Southern Federal University 194 Stachki Ave.Rostov-on-Don 344090Russia

X-ray diffraction studies of synthesized Ba_(2)TiSi_(2)O_(8) have shown that this compound has a fresnoite structure and is characterized by a polar phase P4bm at room *** synthesis of Pb_(2)TiSi_(2)O_(8) in the fresnoite phase under the selected synthesis conditions has led to the formation of a perovskite tetragonal phase P4mm corresponding to PbTiO_(3).

关键词： Structure fresnoite A_(2)TiSi_(2)O_(8)minerals ferroics

Peculiarities of the dependences of the dielectric properties of solid solutions of multicomponent systems on the electronegativity of their constituent cations

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Journal of Advanced Dielectrics 2022年第4期12卷 18-23页

作者： Andryushin Konstantin Dudkina Svetlana Shilkina Lidiya Sahoo Sushrisangita Moysa Maksim Andryushina Inna Verbenko Iliya Reznichenko Larisa research institute of physics Southern Federal UniversityStachki str.194 Rostov-on-Don 344090Russia

Solid solutions(SS)of 3-and 4-component systems based on lead titanate-zirconate were prepared by the method of solid-phase reactions and uniaxial hot *** dependences of the relative permittivity of polarized samples on the electronegativity(EN)of their constituent cations have been *** ferro-hardness of the SS(the stability of the domain structure to external influences)is shown to be directly dependent on the EN of elements B in the corresponding oxidation states,i.e.,the degree of covalence of the B-O *** deviation from this dependence in SS with Ni and Cd is explained by their individual features,which result in changes in the degree of bond covalence in both cationic *** conducted crystal-chemical analysis made it possible to choose promising SS when creating ferroelectric materials,including textured piezoelectric ceramic materials for piezoelectric transducers for various purposes:Piezotransformers,piezoelectric motors,ultrasonic emitters,filter devices,ultrasonic flaw detectors,accelerometers,etc.

关键词： Solid solutions multicomponent systems lead titanate-zirconate electronegativity dielectric properties

Phase states and electrophysical properties of multicomponent perovskite solid solutions on the base of PMN-PT and PZT systems

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Journal of Advanced Dielectrics 2020年第1期10卷 68-73页

作者： Aleksey Pavelko Lidiya Shilkina Larisa Reznichenko research institute of physics Southern Federal University 194 Stachki av.Rostov-on-Don 344090Russia

Phase diagrams were constructed(at room temperature),the dielectric,piezoelectric,elastic and reversible properties of the Gemodified xPbTiO_(3)-yPbZrO_(3)-zPbNb_(2/3)Mg_(1/3)O_(3) multicomponent system ceramics were *** data obtained are compared with the results of studies of solid solutions of basic binary systems,as well as with the results obtained previously for other sections of the system under consideration.A significant increase in the width of the morphotropic region,diffusion of the concentration dependences of the electrophysical characteristics,and an increase in stability under the influence of constant bias fields in the solid solutions of the studied system were established.

关键词： Ferroelectrics ceramics multicomponent system phase diagrams piezoelectric properties

Structure and dielectric properties of solid solutions Bi_(7)Ti_(4+x)WxNb_(1-2x-0.1)V_(0.1)O_(21)(x=0.1-0.4)

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Journal of Advanced Dielectrics 2020年第1期10卷 48-54页

作者： S.V.Zubkov research institute of physics Southern Federal University Stach.Ave.194Rostov-on-Don344090Russia

The structural and electrophysical characteristics of a number of solid solutions of layered oxides of the perovskite-type Bi_(7)Ti_(4+x)WxNb_(1-2x-0.1)V_(0.1)O_(21)(x=0.1-0.4)are *** to X-ray powder diffraction data,all the compounds studied are single-phase and have the structure of Aurivillius phases(m=2.5)with a rhombic crystal lattice(space group I2 cm,Z=2).Changes in tetragonal and rhombic distortions of perovskite-like layers in compounds were considered depending on their chemical *** temperature dependences of the relative permittivityε(T)were *** was shown that the Curie temperature T_(C) of the perovskite-type oxides Bi_(7)Ti_(4+x)WxNb_(1-2x-0.1)V_(0.1)O_(21)(x=0.1-0.4)linearly decreases with increasing parameter *** activation energies of charge carriers were obtained in different temperature *** was found that there are three temperature regions with very different activation energies due to the different nature of the charge carriers in the studied *** effect of substitution of Nb^(5+) ions by V^(5+) ions is *** was found that for a number of compounds,the substitution of niobium ions by vanadium ions led to an increase in the dielectric constant and a decrease in the dielectric loss tangent.

关键词： Aurivilliusphases Bi_(7)Ti_(4+x)WxNb_(1-2x-0.1)V_(0.1)O_(21) Curie temperature(T_(C)) tolerance factor

Crystal structure,microstructure,electrophysical properties,and thermally induced aging of PZT-CdNb_(2)O_(6)ceramics

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Journal of Advanced Dielectrics 2022年第5期12卷 1-11页

作者： Andryushin Konstantin Pavelko Alexey Sahoo Sushrisangita Shilkina Lidiya Nagaenko Alxandr Andryushina Inna Moysa Maksim Reznichenko Larisa research institute of physics Southern Federal University Rostov-on-Don344090Stachki str.194Russia institute of High Technology and Piezo Technic Southern Federal University Rostov-on-Don344090Milchakova 10Russia

Solid solution samples of the three-component system(1−x)Pb(Ti_(0.5)Zr_(0.5))O_(3)−xCdNb_(2)O_(6)with x=0.0125-0.0500,Δx=0.0125 were obtained by solid phase synthesis followed by sintering using conventional ceramic *** crystal structure,microstructure,electrophysical,and thermophysical properties of these ceramics have been *** is shown that all studied solid solutions can be divided into two groups(with x=0.0125 and with x>0.0125),characterized by different characteristics of the change in properties with variations in external *** is probably due to the transition from a perovskite-type structure with a tetragonal(T)unit cell to inhomogeneous solid solutions consisting of a series of T-phases with similar cell parameters.A conclusion is made about the expediency of using the data obtained in the development of similar materials for devices based on them.

关键词： PZT CdNb_(2)O_(6) XRD microstructure piezoelectric properties thermophysical properties phase transition fatigue